The Geometry of Packing

Rolling vs. Folding: An Interactive Essay

1. Intuition vs. Reality

When packing for a trip, the eternal debate is Folding vs. Rolling. Intuition suggests that rolling clothes compresses them, saving massive amounts of space. But is that true?

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Adjust the slider to make your prediction.

Surprising? In controlled experiments, both methods consume the exact same volume. A cotton fiber is a solid; you can't change its volume just by bending it differently. However, that doesn't mean the methods are equal.

2. Conservation of Volume

A t-shirt is a deformable solid. Whether you fold it into a rectangle or roll it into a cylinder, the amount of fabric remains constant. The only variable that changes volume is Air.

Mass
Volume = Mass / Density
Changing shape does not change volume. Only Compression (Force) does.

3. The Bin Packing Problem

If volume is conserved, why do travelers prefer rolling? It solves the Bin Packing Problem. Suitcases aren't perfect rectangles—they have wheel wells and handle ridges. Large rigid shapes (folded clothes) waste space in corners.

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Observation: Notice how "Folded" blocks bridge over the corner wheel-wells, creating empty void space (white gaps). "Rolled" units tumble into the gaps.

4. The Algorithm of Time

The most significant difference found in the experiment wasn't space, but Time. Rolling is a simpler algorithm to execute with fewer steps (Fold half, Roll fast) versus Folding (Align seams, flatten, fold, fold, smooth).

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Fold
15m
Roll
9m
Rolling is O(n) efficient. Folding scales poorly with perfectionism.

5. The Exception

Algorithms have edge cases. The video notes one major exception: The Collared Shirt. Rolling applies stress to the fabric structure.

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Status: Safe (Flat)